Remote control system

ABSTRACT

A remote control system employs transmitting and receiving apparatus housed and arranged in configurations which are particularly adaptable for use in a home, dwelling, etc., for eliminating the necessity of extra wiring and outlet boxes. The transmitting units are mounted in housings resembling conventional wall switchplates normally found in the home; while the receiving units are mounted in housings which resemble normal AC receptacle outlets. The transmitter housings include switching means for selectively activating the transmitter included therein, and causing the same to propagate a predetermined frequency signal which is responded to by a receiving unit mounted in a receiving unit housing coacting with any one of a plurality of existing AC wall mounted receptacles to operate any one of these existing receptacles on a selective basis.

United States Patent [72] Inventor Daniel Peters 109 Ludlow Ave., Springlake, NJ. 07762 [211 App]. No. 814,125 [22] Filed Apr. 7, 1969 [45] Patented June29,1971

[54] REMOTE CONTROL SYSTEM 3 Claims, 17 Drawing Figs.

[$2] 0.8. CI 307/140, 7 317/147, 325/37. 340/171 [51] Int. Cl H0111 47/20 [50] Field of Search 307/1120, 129. 140; 317/147; 340/171; 343/225; 325/37 {56] I References Cited UNITED STATES PATENTS 3,287,722 Tl/1966 Craig 317/147 UX 3,299,284 1/1967 Hough 325/37 UX 3,440,347 4/1969 Spencer etal. 307/140 UX 3,445,848 5/1969 Goldstein 317/147 X Primary Examiner- Robert K Schaefer Assistant Examiner-William J. Smith Attorney-Arthur L. Plevy ABSTRACT: A remote control system employs transmitting and receiving apparatus housed and arranged in configurations which are particularly adaptable for use in a home, dwelling, etc., for eliminating the necessity of extra wiring and outlet boxes.

The transmitting units are mounted in housings resembling gift 01C AMI? PATENTED JUNEQIQH 3.590271 SHEET 1 0F 3 i I +21) 2? i 2A. 34 42 W INVFNTOR REMOTE CONTROL SYSTEM .This invention relates to a remote control system, in general, and more particularly to such a system comprising remotely operated receivers with associated transmitters, arranged in wall switch and outlet configurations, adaptable for use in a home or dwelling and for controlling electrical loads.

The prior art is replete with devices which are broadly classified as remote control systems, and which function to supply electrical power to a suitable appliance such as a television receiver, radio and so on.

Such prior art schemes utilize a hand-held transmitter, which may operate in the ultrasonic, radio frequency (RF) or other allocated band. A receiver located within the appliance selectively responds to the transmitted signal to operate a relay or other device and thus applies electrical power thereto.

A common need in homes or dwellings is the requirement for a wall switch to control a'specific outlet. Many times a switch is available, but it may control the wrong outlet. In other instances, the switch is not present at all. Adding such switches can be expensive, time consuming and difficult; and

is a type of task the average homeowner is not capable of personally implementing.

In spite of this, the concentrated efforts disclosed in the prior art, pertaining to remote control systems, there nevertheless does not exist an inexpensive and reliable system to meet this need within the home or otherdwelling places.

It is therefore an object of the present invention to provide a remote control system which is simple and economical to construct and operate.

Another object of this invention is to provide a remote control system employing an economical transmitter unit ar ranged in a wall, switchlike housing normally found in the home.

A further object is to provide economical remote control systems employing receivers and transmitters arranged in suitable enclosures adaptable for coacting with or plugging into conventional electrical outlet configurations.

In accordance with a feature of this invention, a transmitter and receiving apparatus are provided for use in a remote controlled system, particularly suited for operation within a wall enclosed area or room; the transmitter unit are located within first hollow housings, having switch means mounted thereon for coupling a source of power to a transmitting unit included in said housing, for energizing the same. The transmitter housing, as fabricated, may be of the approximate dimensions, but slightly thicker, than a conventional wall switchplate normally found in a room or home.

Upon energization of the transmitting unit a frequency signal is caused to propagate and is selectively captured by a receiver unit mounted within a second hollow housing and having a male receptacle mounted on a back surface thereof, which receptacle coacts with any one of a plurality of AC receptacles normally found within said walled enclosed area. The receiving unit activates a relay circuit which couples AC power from said male receptacle to an AC receptacle mounted on the front surface of the housing.

In this manner the transmitter wall housing, having a back surface adapted for mounting said housing on one of said walls at any predesired location, can selectively energize one receiver unit contained in said second housing, which is plugged into any one ofa plurality of existing AC wall receptacles by means ofsaid back surface mounted male receptacle.

Other embodiments and features show unique and novel receiver configurations employing a plurality of threshold circuits to offer improved noise immunity for such remote control systems as will be further explained and described.

The novel features which are considered to be characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its utilization, organization and method of operation as well as to further objects and advantages thereof, will best be understood from the following description when read in connection with the accompanying drawings in which identical numerals reference similar components and in which:

FIG. I is a plan view ofa portion of atypical room employing electrical outlets and wall switches useful in explaining the invention;

FIG. 2 is a front plan view (FIG. 2A), a side plan view (FIG. 2B), and a back plan view (FIG. 2C) of a remote control transmitter wall switch housing assembly according to this invention; 7

FIG. 3 is a perspective plan view of a switch lever plate as shown in FIG. 28;

FIG. 4 is a sectional side plan view used in explaining the switching mechanism as utilized in the transmitter assembly of FIG. 2A, taken about line 4-4; I

F IGS. 5 and 6 are schematic diagrams of transmitter units as may be contained in the housings of FIG. 2;

FIG. 7 shows another embodiment of a schematic representation of a transmitting unit;

FIG. 8 shows a front plan view (8A) and a side plan view (88) of a receiver unit housing according to this invention;

FIG. 9 is a schematic diagram in block form of a receiving unit;

FIG. 10 is an electrical schematic diagram of an ultrasonic receiver unit for use with the invention;

FIGS. 11 and 11A are electrical schematic diagrams of transmitting units for use with this invention;

FIG. 12 is a circuit diagram of an alternate embodiment of a receiving unit; and

FIG. 13 is a circuit diagram ofa receiving unit according to the invention.

Referring to FIG. 1 there is shown a plan view of two walls 10 and 11, in part sectional view, and a doorway 12.

In most homes, office buildings and so on, a similar room, office or other arrangement exists together with AC wall receptacles as 15 and 16, for accommodating various appliances, lighting fixtures and other devices, which require electrical power in order to properly operate. Shown in FIG. 1 is a lamp 17, having an on-off switch 18 with a line cord 19 terminated at one end with a male plug receptacle 20, for insertion into an AC wall receptacle as 15 or 16. The AC receptacles l5 and 16 are energized by coupling suitable terminals of the receptacles to AC power lines 21 and 22, originating from a common source, in the home as a control fuse box and so one. The AC lines 21 and 22 are routed and fixed in place during the construction of the home or building prior to the construction of the walls 10 and ll of the room and the floor.

The walls and floors are then constructed so that the power lines 21 and 22 are enclosed within the hollows between walls 10 and 11 or beneath the floor and are not easily accessible without breaking into or in some other costly manner damaging both the walls and floor.

During the routing of the AC power lines 21 and 22 a wall switch 25 may also have been provided by the electrician or builder and coupled to the power lines, so that one of the receptacles 15 or 16 can be selectively energized by the operation of the switch 25. In this manner there is shown the power lines 21 and 22 coupled directly to the proper terminals of the AC receptacle 15. The power line 21 is also coupled to a proper terminal of the AC receptacle 16 while the power line 22 is coupled to the other terminal of receptacle 16 through the wall switch 25.

Alternatively, the home so prewired may not include a wall switch 25, and therefore both AC receptacles 15 and 16 are prewired to the power lines 21 and 22 directly. This configuration is alluded to in the drawing by showing the wire 22, which would correspond to line 22 in the absence-of the wall switch 25.

With the arrangements shown in FIG. 1, the wall switch 25 when operated will energize the light bulb of lamp 17 if the on-off switch 18 is in proper position. Hence as an individual enters the room, via doorway 12, he may operate the lamp 17 via the wall switch 25. It is also clear, that if the room were not so provided with the wall switch 25', operation of the lamp 17 would be strictly under the control of the on-off switch 18.

At least two problems can be seen arising from the above arrangem'ents.

Firstly, assume that one desires to locate the lamp 17 at a location near receptacle l; and hence inserts the line cord 19 of the lamp 17 (via the male plug 20) into receptacle 15. This action therefore removes the desired control of the lamp 17 from the wall switch 25. To solve this problem, one would have to run an extension line from receptacle 16, which is wall switch controlled, to a new AC receptacle which may be mounted on the wall or otherwise near the new position of the lamp 17. g

' In order to prevent accidents, and to further mask the exterision wire from view, the extension wire routing path may be'under a rug or behind a molding, or otherwise tortuous in nature, requiring extra length of wire and a great deal of time to so implement. If one desires to insert the wire through the walls, by a so called snaking" technique this may require considerable time or actually be impossible to implement, due to obstruction of beams, insulation and so on included within the hollows between walls or beneath the floor (i.e. second storyhomes, etc.). In any event if the homeowner or other person is not familiar with electrical connections, as is the common case, he would employ the services of an experienced electrician at a relatively large expense.

Oftentimes, a wall switch does not exist, at all, and if one desires to so control a lamp or other device a switch as 25 has to be added. I

This, of course, is still a greater problem as the wiring, the routing, together with the masking of the new wire paths; plus the inclusion of the switch receptacle and box, is an expensive, time consuming, and difficult task. In general, such an electrical job is most likely beyond the capabilities of the average homeowner, so that he is forced to hire an electrician.

Referring to FIG. 2 there is shown front (2A), side (2B) and back (2C) plan views of a remote control transmitter housing according to the invention.

The housing 30 is fabricated, by molding or otherwise from a suitable plastic material and may be of a rectangular or other symmetrical pleasing configuration having a length and width greater than the'thickness of the sides. The housing 30 has the appearance of, and is preferably dimensioned, as a conventional switch wallplate unit, normally found in the home, but may be slightly thicker as will be explained subsequently.

The back surface 31 of the housing 30 as seen in FIG. 28 may be' stippled, scored or otherwise roughed or treated, adapting it for cementing to a wall (as 11 of FIG. I) at a desired location, determined by the user. Alternatively, the back surface 31 may be treated with a suitable glue and covered by a waxed paper layer. When a location is selected the paper is removed and the unit 30 pressed into place.

The housing 30 has a battery accommodating hollow or recess 32 on the front surface 33. A battery 34 is located within hollow 32 for easy removal from the front of the housing when replacement is required. The battery 34 is coupled to a transmitter assembly35 by means ofa conventional plug assembly 37 having a positive and negative terminal and associated wires. The battery 34, may be that as found in most portable radios and so on. The battery 34, as shown therefore may be a conventional 9 volt NEDA1604 type, commonly employed in transistor radios, etc. A hole in the front surface of the housing 30 accommodates a mesh plug unit '36, which is force fitted or otherwise secured therein, to permit easy propagation of the RF or ultrasonic oscillations afforded by a transducer mounted on the transmitter assembly 35, through the holes in the mesh unit 36.

Surrounding the battery accommodating recess 32 is a flange 38, molded as part of the housing 30. The flange 38 has a lip or bottom curved channel and a top lip 40 for accommodating wire spring members 44 and 44' associated with a switch lever plate 42.

Referring to FIG. 3 the switch lever plate 42 is shown more clearly. The plate 42 may be fabricated from plastic or a suitable metal and is dimensioned to be larger then the flange 38 surrounding the battery hollow 32. A wire member 44 is located near the bottom end of the lever plate 42 and a wire member 44' is located near the top end of the lever plate 42.

A rubber or resilient member 43 is located nearer the top end of the lever 42 and is cemented or otherwise fastened to the inner surface of the switch lever plate 42.

Referring to FIG. 28, a side view of the switch lever plate 42 is shown physically coupled to'the side view embodiment of the switchplate housing 30. With the battery 34 positioned as shown, one merely pushes or forces the switch lever plate 42 about the flange surface of the housing 30 directly above the battery recess 32. The springlike wire members 44 and 44' (as shown) are forced onto the lips 40 and 40' within the accommodating channels, thereby securing the lever plate 42 to the housing 30.

The flange 38 has a hole 45 therein, which coacts with a hollow, contiguous with the battery hollow 32, containing switch arrangement.

The switch comprises two flexible, conductive contacts 46 and 47, as relay contacts and so on, fabricated from a suitable conductive metallic material. The flexible contacts 46 and 47 are secured to the housing, at one end thereof, by means of screws, or otherwise, and are preassembled through a suitable access area which may be provided for on the back or front surfaces of the housing. The contacts 46 and 47 as secured do not touch each other or otherwise make contact. A proper wire from the battery 34 is prewired to one contact as 46 while a wire from the transmitter assembly 35 is wired or soldered to the other contact 47. A small rod 48 is inserted through the hole 45, as more clearly shown in FIG. 4. The rod or other suitable member 48, extends beyond the flange 38 of the housing 30 and is slideably mounted within the hole 45. With the lever plate 42, positioned with the wire spring members 44 and 44 coacting the lips of the flange 38, as described above, the rubber or resilient member 43 rests on the battery surface and the rod 48 touches the back surface 50 of the switch lever plate 42. If a force is exerted on the front surface of the lever plate 42 the resilient member 43 compresses, the lever plate 42 moves, forcing the rod 48 to engage the flexible contact 46 thus moving the same to contact member 47. In this position the wire labeled from battery is connected through the contacts 46 and 47 to the transmitter assembly 35.

The housing 30 as fabricated may have an exposed back surface 31 which is finally covered by a treated cover plate, as described above, which may be permanently secured or fastened thereto by suitable means.

FIG. 2C shows a back view of the housing 30 showing the contacts 46 and 47, 'the battery 34 and the transmitter assembly 35.

Briefly, when the switch lever plate 42 is pushed the rod 48 closes the contacts 46 and 47 and power from the battery 34 is coupled to the transmitter assembly 35, which oscillates at a predetermined frequency and causes such oscillations to propagate through space by means of a suitable transducing unit (as an antenna and so on) included on the transmitter assembly 35.

Referring to FIG. 5 there is shown a schematic, using electrical symbolization, to further explain the operation of the contents of the assemblies shown in FIGS. 2, 3 and 4.

The battery 60 may be a 9 volt, transistor radio, type which is preferably longer and wider then it is thick. The battery thickness is determinative of the thickness of the assembly of H6. 2, as can be seen. The battery 60 has one terminal permanently connected to the oscillator 61 and a second terminal coupled thereto via the switchable contact 63. The output terminals of the oscillator 61, are coupled to suitable transducer 64. Transducer 64 is shown schematically as an ultrasonic transducer, which are-known in the art. Accordingly, the oscillator 60 provides a frequency signal in the ultrasonic range (i.e. 35 to 40 kHz.) which is caused to propagate through space due to the transducer 64 action.

FIG. 6 shows a similar schematic to that of FIG. 5, showing the battery 60, switch 63 and an oscillator 65 with a loop-stick antenna 66 adapted to operate in the 160-190 kHz. band, which band is presently allocated for remote control systems. Many examplesof suitable transmitting arrangements can'be accommodated within the housing or assembly 30 shown in FIG. 2 and, as such, are known in the prior art.

A particularly useful and economical configuration will be shown and described subsequently, in greater detail. It is also known that one can utilize a tuning fork or other mechanical type oscillator assembly and suitable transducing equipment, mounted within the housing 30 as shown in FIG. 2, and thereby eliminate the requirement for the battery 60. How ever, many such units are too bulky and expensive for conveniently so incorporating.

FIG. 7 shows a transmitting unit schematic containing an oscillator 67 and suitable transducer 68 for plugging into a wall receptacle by means of the male connect or 70. The coacted AC wall receptacle also furnishes operating power thereto, by energizing a power supply 69, as will be further described and explained subsequently.

Referring to FIG. 8A there is shown a front view of a receiving unit 80 according to this invention. The unit 80 has one orimore conventional AC receptacles 81 and-82-mounted on the 1 front surface thereof.

FIG. 8B shows a side view of the receiving unit'80. The unit 80 has mounted on a back plate or surface, a male plug adapter 83 for insertion into a conventional AC wall receptacle. A receiving transducer unit 84 is coupled to a selective filter 85 which is followed by a high gain or selective amplifier 86. The electronic assembly, as shown, generally by the above noted components, is located and mounted within the receiver assembly housing 80.

A wire 87 couples one terminal of the AC male plug adapter 83 to a terminal ofthe female AC receptacles 81 and 82 and is used as a common lead or reference potential bus for the receiver unit. The other terminal of the male plug 83 is coupled to the input of a power supply module 88 to energize the amplifier 86 and other receiver circuitry, as will be further described. This terminal of the male plug 83 is also coupled to a module 89 containing a suitable power switch as a relay circuit and contacts, or an S.C.R. circuit equivalent in operation to a relay and used for selective coupling of a AC power to receptacles 81 and 82.

The module 83 is coupled to the output of the high gain amplifier 86 and is energized when the receiving unit 80 receives a suitable transmitted oscillatory signal within the frequency band-pass of the filter 85 included therein. Such a signal is generated by a transmitting wallplate unit as described in FIGS. 2, 5, 6 and 7. In this manner operation of the power switch module 89 completes the connection from the male plug 83 to the front mounted receptacles 81 and 82 mounted on the receiving unit 80. i

As seen from the front view, or FIG. 8A, the receiving unit 80 appears as a conventional AC receptacle as normally found in a home and so on.

The electrical components forming the transmitter shown in FIG. 7, are also easily accommodated in a housing 80 as shown in FIGS. 8A and 8B. If so mounted, an existing wall switch (as 25 of FIG. 1) positioned on a wall in a room may control any desired wall mounted AC receptacle (as of FIG. 1). Accordingly, one would insert a transmitter unit as shown in FIG. 7, contained within a housing 80 (as 80 shown in FIGS. 8A and 8B), into the prewired AC receptacles (as 16 of FIG. 1). The switch would still selectively energize one of the receptacles 81 or 82 corresponding to 81 and 82 of FIGS. 8A and 8B, as seen from FIG. 7. However, the activation of the switch would also couple AC power from the receptacle (16 of FIG. 1) to the power supply unit 69 (FIG. 7); and thusly, energize the oscillator 67 to cause a signal to propagate via transducer 68. A receiving unit plugged into receptacle 15, would respond to the transmitted signal and energize the receptacles 81 and 82 of FIGS. 8A and 8B.

Thus, if a homeowner or other. person, inserted a transmitter unit (FIG. 7) housed within a housing of FIGS. 8A and 88) into receptacle 16 and inserted a receiver unit (80 of FIGS. 8A and 88) into receptacle 15, the existing wall switch (25 of FIG. 1) would serve to activate any appliance (as lamp 17 of FIG. I) inserted in the receiver AC receptacle as 81 or 82 when activated. This action eliminates the need for the user to utilize extension cords, run new wires, provide new receptacles or boxes, and so on.

FIG. 9 shows a schematic diagram in block form of the electrical circuit included in a receiving housing 80 as shown in FIG. 8 andadaptable for responding to and receiving RF signal transmissions for an RF wall switch mounted transmitter, as shown in the electrical schematic of FIG. 6. The modules and related functions, shown in FIG. 9 are well known in the prior art, as is this particular schematic for a remote control receiver.

FIG. 10 shows an electrical schematic of ultrasonic receiver circuitry whose physical counterparts can be accommodated within a'housing 80 as shown in FIG. 8.

The receiver employs an ultrasonic receiving transducer 90, which may be a frequency selective microphone. Hence the transducer performs selective'filtering, as well as being sensitive to propagated ultrasonic (35 to 40 kHz. signals. The transducer 90 is followed by a high gain amplifier 91 which amplifies the low level received signal and applies the same to a rectifier circuit 92, including a proper filter at an output, for providing a DC voltage proportional to the amplified frequency signals received. The rectifier circuit 42 may comprise a full or half wave rectifier in a bridge or other well known configuration together with an output R-C, R-L, or RLC network having a time constant suitable for providing a low ripple DC voltage. The rectified DC is applied to a DC threshold amplifier 93 for actuating a bistable multivibrator 94 or flip-flop (F/F) circuit.

The flip-flop circuit 94 has two stable states. One state serves to energize the power switch module 95, which may be a silicon controlled rectifier (SCR) circuit or an electromecl'ianical relay. Energization of the power switch 45 connects the wire 98 to the wire coupled to receptacle 96 via the low impedance path of the power switch 95.

Power for the receiver is provided for by a power supply (P.S.) circuit 99 which is energizedby the AC power applied to the male connector 97, when plugged into a conventional AC wall receptacle.

Generally, the receiver of FIG. 10 operates as follows:

Assume, the F/F 94 is initially in one stable state, corresponding to the inactivation of the power switch 96. The male plug 97 is inserted into an AC wall receptacle and the power supply 99 energizes the modules as shown. A ultrasonic wall switch transmitter, in a housing (as 30 shown in FIG. 2) is energized and propagates the ultrasonic signal. The transducer 90 responds to and applies the received signal to the amplifier 91, the amplified signal is rectified and filtered, and a DC threshold voltage triggers the flip-flop 94 to change the state. The change of state energizes the power switch 95, thereby coupling full AC power as applied to male plug 97, from an AC wall receptacle to the female outlet 96 (as 81 of FIG. 8) mounted on a receiver housing (80 of FIG. 8

Referring to FIG. 11 there is shown an electrical schematic of a suitable transmitter unit for inclusion in a housing as shown in FIG. 2.

A transistor 100 is used in an oscillator configuration, having a base electrode coupled to a terminal of a suitable frequency selective feedback network 101, containing inductors and capacitors. Suitable oscillator arrangements are well known for use in the ultrasonic band as Colpitts, Hartley and so on. See for example a text entitled Functional Circuits and Oscillators" by Herbert J. Reich, D. Van Nostrand, Inc. 1961, Page 349 for suitable configurations.

The switch 102 corresponds to the switch mechanism mounted on the front of the transmitter switch, wallplate, like housing (FIG. 2) and serves to couple the battery 104 thereto lator and thus cause oscillations. The feedback network 101 is fabricated as a transponder or transducer as well, and permits propagation of the frequency signal through space. Such units are well known in the art and for example have been used in remote control television'systems. I

' The circuit shown in H0. 11 need only employ a single transistor 100 and two resistors 105 and 106 used for biasing and base current limiting respectively. The components are physically small and not critical as to selection and are therefore easily accommodated in a suitable transmitter housing (30 ofFlG. 2).

FlG. 11A shows apower supply unit for use with a transmitter mounted in a housing as shown in FIG. 8. The male plug 109 (of FIG. 8) supplies AC power to the half wave rectifier unit including diode 108, and capacitor 110. A resistor 107 furnishes a voltage drop to bias the zener diode 122 ,which has a rating equal to the battery rating used in FIG. 11.

- FIG. 12 shows a schematic of a receiving circuit for ultrasonic transmissions. An ultrasonic selective microphone l11 is coupled to the input of an operational amplifier 112 which is preferably a high gain type and of an integrated circuit construction. An example, of a suitable type is the CA3035 manufactured by R.C.A., Electronic Components and Devices, Harrison, New Jersey. See a publication entitled CA3035 Ultra High-Gain Wide-Band Amplifier Array," File No. 274, 6-67, wherein a typical remote control unit and suitable component values are shown, similar to that of FIG. 12.

Briefly, FIG. 12 further shows a male receptacle 115 which when inserted into a suitable AC wall receptacle will energize the power supply comprising the current limiting resistor 117, the rectifier 118 and the filter capacitor 119 and therefore supply operating potential to amplifier 112.

A portion of the integrated circuit amplifier 112 is used as a rectifying element. lf reference to the above noted publication (CA3035) it can be seen that such amplifiers comprise a plurality of monolithic integrated circuit amplifier configurations on a common substrate. By operating certain stages, thereof, without applying biasing potential, one can use the monolithic transistors in nonlinear rectifying circuits and therefore the output of the amplifier 112 is a rectified AC signal which when applied to capacitor 124 develops a DC potential thereacross proportionalto the amplitudeof the transmitted signal. When the DC voltage across the capacitor 124 is approximately equal to the DC across the zener diode 123, the relay coil 122 is not energized, and power is applied to the AC receptacle 116 via contact 113. As soon as a transmission ceases the voltage across capacitor 124 decreases and the relay is energized. Relay 122 is an impulse type and may include a mechanical locking mechanism, holding coil or contact, which retains the relay contact 1l3 in the activated position until another transmission occurs thus opening contact 113. Such impulse or sequencing relays 122 are known in the prior art.

Accordingly, as one enters a room or area and depresses the switch lever plate of the transmitter wall unit (30 of FIG. 2) the signal transmission activates the receiver relay 122 which applies AC line potential via contact 113 to receptacle 116.

The impulse relay 122 locks in this position. As one leaves the room the transmitter switch lever plate is again depressed, releasing the relay contact 113 and locking it in the open position.

Referring to FlG.-13 there is shown a receiver unit capable of responding to ultrasonic frequency transmissions, which employs inexpensive transistor 'components, and further eliminates the necessity of using an impulse type relay as previously described in conjunction with FIG. 12.

An ultrasonic transducer or selective microphone 130 is coupled to the input electrode of a high gain amplifier 131 preferably of an integrated circuit configuration and as indicated above commercially available. The output terminal 132 of the amplifier is coupled to a filtering capacitor 133 connected between the output terminal and a source of 8 reference potential. A load resistor 134 couples the output terminal of the amplifier to a source of potential through a dropping resistor 135.

The source of potential comprises resistor 136, rectifier 137 and filter capacitor 138 and is energized by inserting the male receptacle 139 in an appropriate wall mounted AC power receptacle. A stabilized operating voltage for the amplifier 131 is obtained from zener diode 140 coupled between the junction of resistors 134 and 135 and ground. The output terminal 132 of the high gain amplifier 131 is coupled to the cathode electrode of a zener diode 141; having an anode electrode directly coupled to the base electrode. of a transistor 142. Transistor 142 has the emitter electrode coupled to ground and the collector electrode coupled to a source of potential through a load resistor 144.

The collector of the DC amplifier transistor 142 is coupled to one terminal of a filter capacitor 145 having the other terminal coupled to ground. A neon bulb has one terminal coupled to the collector electrode of transistor 142 and another terminal coupled to ground through a resistor 151. The neon bulb, as will be described, is used for generating triggering pulses for a bistable multivibrator or flip-fiop circuit comprising transistors 152 and 153.

The flip-flop arrangement is triggered by a pulse coupled across capacitor 156'which is connected between resistor 151 and the base electrodes of transistors 152 and 153. The base electrodes of transistors 152 and 153 are coupled to the other terminal of the capacitor via resistors 157 and 158. A common emitter electrode return path for bothtransistors is provided by resistor 159 coupled between the respective emitter electrodes and a point of reference potential, such as ground.

The base resistors 157 and 158, as coupled to the terminal of capacitor 156, areshunted to ground through a resistor 160. Suitable regeneration is provided for the flip-flop circuit, by resistors 161 and 152, coupled respectively from the collector electrodes of transistors 152 and 153 to the opposite base electrodes thereof.

A collector load is provided for transistor 153 by resistor 164 coupled between the collector electrode and the source of operating potential. The collector electrode of transistor 152 is coupled through a resistor 165 and a relay coil 166 in series to the source of operating potential. The relay coil 166 has associated therewith a contact 167 having one terminal thereof coupled to one side of the female receptacle 170, havingits other terminal coupled to the ground side of the line. The operation of the circuit thus described is as follows.

For the absence of an ultrasonic transmission or ultrasonic frequency propagation the voltage at output terminal 132 of the amplifier 131 is positive. The zener diode 141 is conducting and serves to forward bias transistor 142, thereby producing a low collector voltage. There is little charge developed across capacitor 145 during this mode and the transistor multivibrator is in the state corresponding to current flowing through resistor 164.

Accordingly, there is little current flowing through the relay coil 166 and hence contact 167 is open and no AC line power is coupled to terminal 170. If one activated a suitable ultrasonic wall mounted transmitting unit to cause'an ultrasonic frequency propagation the following operations would occur.

The selective transducer 130 responds to the propagated signal and applies the same to the amplifier 131. The amplifier 131 provides an AC rectified type signal which is filtered by capacitor 133 until the voltage across the capacitor is no longer sufficient to maintain the zener diode 141 in conduction. This reverse biases transistor 142 and permits the collector electrode to go towards the supply potential. Capacitor 145 charges through resistor 144 towards the supply potential until the voltage thereacross is sufficient to break down the neon 150.

The capacitor 145 discharges through the neon 150 and resistor 151 to provide a positive pulse coupled through capacitor 156, which pulse couples to the base electrode of transistor 152; thus turning on. transistor 152. The collector voltage of transistor 152 drops to a low value and by regeneration turns off transistor 153. The collector current flowing through transistor 152 is sufficient to operate the relay contact 167 via the coil 166. AC power is now available at receptacle 170. The flip-flop maintains this state until another transmission occurs wherein the samesequence of events takes place, thus transferring-the flip-flopback to its initial state and thereby serving to remove power from receptacle 170 by opening contact 167. I

The circuit shown in FIGL13, provides extreme immunity against spurious noise pulses from operating the multivibrator. The ultrasonic frequency. band (35 to 40 kHz. is subjected to interference from many sources of noise, produced by common, every day sounds, For example the sounds accompanying running water (from faucets, showers), the clattering of metal, tolling bells, etc., all have components in the ultrasonic band, 7

in the circuit shown such spurious frequencies because of their-statistical and random nature will not easily trigger the multivibrator described herein. Noise immunity is provided by capacitor 133 which must charge to a sufficient level to reverse bias the zener diode 141. The threshold voltage of the zener diode 141 must be overcome before transistor 142 can be turned on. The incoming signal must persist until capacitor 145 charges through resistor 144 to a suitable level sufficient to trigger the neon 150. if all of these conditions and times are met the flip-flop will exhibit a transition. Due to the nature of noise and the 'power and duration of such noise pulses, it'has been found that such sources are not sufficient to falsely operate a circuit as shown in FIG. 13 which utilized the following components. I 7

Amplifier 131 -'n0ted publication employing a.c. coupling between stages.

1 micromicrofarad. 20 mieromicro arads. mierofarads. 156 ,02 microtarad. Transistors 152, 153 and 143. 2N3568. Neon 150 NE-2. Relay 166 r 2.6K ohms-coil impedance, contact 167 rated at 5 amperes.

The above components were mounted on a conventional phenolic board approximately 2X3inches and contained within a housing configuration as shown in FIG. 8, which resembles a conventional AC wall receptacle. The receiver was selectively energized by a transmitter unit, having the circuit configuration shown in FIG. 11 and contained within the housing of FIG. 2-which was fastened to a wall at a desired lo- (YA-i035 biased as'shown in the above I 10 wall mounted AC receptacles distributed thereabout 'and energized by AC power lines contained and routed 'within hollow recesses between said walls, in combination therewith, a transmitter housing for containing a transmitting unit adapted to transmit through space a predetermined frequency signal when energized by a suitable power source, comprising,

a. a housing, having front, back and side surfaces, forming a rectangular solid having an internal hollow, and further dimensioned so that said width and length of said front and back surfaces are substantially larger than the thickness of said back surface of said side surfaces, said housing further adapted for mounting on one of said walls, said front surface having a hole therein, contiguous with said hollow and surrounded by flanged surfaces extending outward from said front surface, said transmitting unit located within the hollow confines of said housing,

b. a power source, having a first and second'terminal and positioned within 'said hole in said front surface and located within said hollow, for easy removal thereof through said front opening,

c. means, included in said hollow housing for coupling one terminal of said power source to said transmitting unit,

d. switch contact means, having a first flexible contact coupled to said other terminal of said power source and a second flexible contact coupled to said transmitting unit, said switching means located in said hollow of said housing and positioned in a fixed position where said first and second flexible contacts are fixedly mounted at one end and spaced apart at said other end directly above one another,

e. a switch lever unit having front surface and side surfaces extending in the same direction from said front surface, surrounding the periphery thereof, and dimensioned slightly larger than said holein said front surface, for covering the same,

f. means mounted on said switch lever unit within the area confined by said surfaces for coating with said flanged surfaces surrounding said hole for securing said unit to said flange and therefore to said front surface of said housing, said means further permitting motion of said lever unit in directions relatively perpendicular to said front surface, and

g. means coupled between said switch lever unit and said switch contact means for engaging at least one of said switch contact means at said other end, when said lever unit is moved towards said hollow to cause said engaged contact to touch said other contact to thereby couple said power source terminal to said transmitting unit for energizing the same.

2. The transmitter housing according to claim 1 wherein one of said flanged surfaces has a hole therethrough extending into and coacting with said portion of said hollow containing said switch contact means.

3. The transmitter housing according to claim 2 wherein said means coupled between said switch lever unit and said switch contact means comprises,

a. arodlike member slideably mounted in said hole and being of a suitable length for forcing said one of said flexible switch contacts against said other when said switch lever' unit is moved towards said hollow to cause said rodlike member to coact with said switch lever plate and thereby move in said same direction. 

1. In a remote control system of the type employed in a walled room, or a wall enclosed area, containing a plurality of wall mounted AC receptacles distributed thereabout and energized by AC power lines contained and routed within hollow recesses between said walls, in combination therewith, a transmitter housing for containing a transmitting unit adapted to transmit through space a predetermined frequency signal when energized by a suitable power source, comprising, a. a housing, having front, back and side surfaces, forming a rectangular solid having an internal hollow, and further dimensioned so that said width and length of said front and back surfaces are substantially larger than the thickness of said side surfaces, said back surface of said housing further adapted for mounting on one of said walls, said front surface having a hole therein, contiguous with said hollow and surrounded by flanged surfaces extending outward from said front surface, said transmitting unit located within the hollow confines of said housing, b. a power source, having a first and second terminal and positioned within said hole in said front surface and located within said hollow, for easy removal thereof through said front opening, c. means, included in said hollow housing for coupling one terminal of said power source to said transmitting unit, d. switch contact means, having a first flexible contact coupled to said other terminal of said power source and a second flexible contact coupled to said transmitting unit, said switching means located in said hollow of said housing and positioned in a fixed position where said first and second flexible contacts are fixedly mounted at one end and spaced apart at said other end directly above one another, e. a switch lever unit having front surface and side surfaces extending in the same direction from said front surface, surrounding the periphery thereof, and dimensioned slightly larger than said hole in said front surface, for covering the same, f. means mounted on said switch lever unit within the area confined by said surfaces for coating with said flanged surfaces surrounding said hole for securing said unit to said flange and therefore to said front surface of said housing, said means further permitting motion of said lever unit in directions relatively perpendicular to said front surface, and g. means coupled between said switch lever unit and said switch contact means for engaging at least one of said switch contact means at said other end, when said lever unit is moved towards said hollow to cause said engaged contact to tOuch said other contact to thereby couple said power source terminal to said transmitting unit for energizing the same.
 2. The transmitter housing according to claim 1 wherein one of said flanged surfaces has a hole therethrough extending into and coacting with said portion of said hollow containing said switch contact means.
 3. The transmitter housing according to claim 2 wherein said means coupled between said switch lever unit and said switch contact means comprises, a. a rodlike member slideably mounted in said hole and being of a suitable length for forcing said one of said flexible switch contacts against said other when said switch lever unit is moved towards said hollow to cause said rodlike member to coact with said switch lever plate and thereby move in said same direction. 